Chapter 3 Part II: Histology Flashcards
What are the four primary types of tissues?
epithelial, connective, nervous, and muscle tissues
What is the epithelium?
The covering of a body surface or the lining of a body cavity.
What is the function of the epithelium? (7)
-Protection from dehydration
-Protection from chemical and mechanical damage
-Absorption
-secretion
-ion transport
-Filtration
-Forms slippery surfaces
What are the special characteristics of epithelial cells? (6)
• Cellularity
• Specialized contacts/junctions
• Polarity
• Support by connective tissue
• Avascular but innervated
• Regeneration
What does ‘epi’ mean?
surface
What does innervated mean?
contains nerve endings
What does cellularity mean?
composed almost entirely of sheets of cells, separated by minimal amount of extra-cellular material
What does polarity mean in epithelial cells?
they have an upper (apical) and lower (basal) surface
What are the main types of Epithelia?
Surface and Glandular Epithelia
What is the surface epithelia?
consists of tightly packed cells that form a continuous layer covering the body surface (skin) or lining body cavities
What are the glandular epithelia?
secretory epithelial cells that form Exocrine and Endocrine glands
How are epithelia given their name?
First name indicated number of cells, last name describes the shape of the cells
What are the three types of number classifications given for epithelial cells?
simple, stratified, pseudostratified
What are the three types of tissue shapes?
Squamous
Cuboidal
Columnar
What is the basic description of simple squamous epithelium
single layer flat-cells with disc-shaped nuclei
What are the special types of simple squamous epithelium?
Endothelium
Mesothelium
What is the endothelium?
Thin and flattened lining of hollow organs
What is the function of mesothelium?
Lines serous or ventral body cavities and covers visceral organs of those cavities
What are the functions of simple squamous epithelium? (2)
- Passage of materials by passive diffusion and filtration
- Secretes lubricating substances in serosae
Where can simple squamous epithelium be found? (6)
- Alveoli of lungs
- Lining of heart
- blood
- lymphatic vessels
- Lining of ventral body cavity
- covering organs (serosae)
What are simple cuboidal epithelium cells?
single layer of cube-like cells with large, spherical central nuclei
What is the function of simple cuboidal epithelium?
secretion and absorption
Where is the location of simple cuboidal epithelium cells? (3)
- Kidney tubules,
- Secretory portions of small glands, salivary glands and pancreas
- Ovary surface
What is the description of Simple Columnar Epithelium?
single layer of column-shaped (rectangular) cells with oval nuclei
• Some bear cilia at their apical surface
• May contain goblet cells
What is the function of Simple Columnar Epithelium? (2)
• Absorption; secretion of mucus, enzymes, and other substances
• Ciliated type propels mucus or reproductive cells by ciliary action
What is the location of Simple Columnar Epithelium? (6)
• Non-ciliated form
Lines digestive tract, gallbladder, ducts of some glands
• Ciliated form
Lines small bronchi, uterine tubes, and uterus
What is the rule of naming stratified epithelium?
Are named according to the shape of cells at apical (top) layer
What are Stratified Epithelia?
Tissues that contain two or more layers of cells - squamous in shape
What are specific types of stratified epithelia?
Keratinized
Non-keratinized
What is the function of non-keratinized stratified epithelia?
forms moist lining of body openings and tubes where is wear and tear
What is the function of stratified epithelium?
– Protects underlying tissues in areas subject to abrasion
Where is the keratinized stratified epithelia found?
forms epidermis
Where is the non-keratinized stratified epithelia found? (4)
forms lining of esophagus, mouth, anal canal, and vagina
What is the description of stratified cuboidal epithelium?
generally two layers of cube-shaped cells
What is the function of stratified cuboidal epithelium?
protection
Where is the location of stratified cuboidal epithelium?
• Forms largest ducts of sweat glands
• Forms ducts of mammary glands and salivary glands
Describe Stratified Columnar Epithelium
several layers; basal cells usually cuboidal; superficial cells elongated
What is the function of Stratified Columnar Epithelium?
protection and secretion
What is the location of Stratified Columnar Epithelium?
-Rare tissue type
-Found in male urethra and large ducts of some glands
How do you describe Pseudostratified Columnar Epithelium?
• All cells originate at basement membrane, only tall cells reach the
apical surface
• May contain goblet cells and bear cilia
• Nuclei lie at varying heights within cells, gives false impression of
stratification
What is the function of pseudostratified columnar epithelium?
secretion of mucus; propulsion of mucus by cilia
What is the locations of Pseudostratified Columnar Epithelium? (4)
• Non-ciliated type: Ducts of male reproductive tubes and large glands
• Ciliated variety: Lines trachea and most of upper respiratory tract
How can you describe transitional epithelium?
• Basal cells usually cuboidal or columnar
• Superficial cells dome-shaped or squamous
What is the function of transitional epithelium cells?
stretches and permits distension of urinary bladder
Where is the location of transitional epithelium cells?
• Lines ureters, urinary bladder and part of urethra
What do glandular epithelium specialize in?
synthesis and secretion
What are the two main types of glandular epithelium?
Exocrine and Endocrine
What is the difference between endocrine and exocrine glandular epithelium?
exocrine transport their secretion by ducts, while endocrine release their secretion directly in the blood stream
Where do exocrine glands carry their products?
to epithelial surface
What are examples of exocrine glands? (4)
• Mucus-secreting glands
• Sweat and oil glands
• Salivary glands
• Liver and pancreas
Look at the glands, make sure you know all of them
What type of gland has no important example in humans?
Simple alveolar
What is the name of the molecules that endocrine glands produce?
hormones
What are connective tissue made of?
Cells and extracellular matrix
What are the extracellular matrix made up of?
Ground substance and fibrillar components
What is ground substance mainly composed of?
water + Adhesive proteins + charged polysaccharides
What are fibrillar components made of?
- Collagen
- Elastic
- Reticular
What is collagen used for?
tensile support
What is elastic used for?
stretchable fiber
What are reticular?
very fine collagen fibers (forms internal skeleton of soft organs like the spleen)
What is the most diverse and abundant tissue?
connective tissue
What are the main classes of connective tissue?
- Connective tissue proper
- Cartilage
- Bone tissue
- Blood
What is the common embryonic origin of connective tissue?
mesenchyme (mesoderm)
What are the main function of Connective Tissue Proper? (5)
• Support and binding of other tissues
• Holding body fluids
• Defending body against infection
• Storing nutrients as fat
• Fibroblasts produce the protein fibers
What are the two main subclasses of Connective Tissue Proper?
• Loose connective tissue
• Dense connective tissue
Describe areolar connective tissue and the cells it contains
• Gel-like matrix with all three protein fiber types
• Cells – fibroblasts, macrophages, mast cells, white blood cells
What is the function of areolar connective tissue? (4)
• Wraps and cushions organs support
• Holds and conveys tissue fluid
• Important role in inflammation
• Surrounds small nerves and capillaries
Look at Areolar CT diagram
What is the function of Adipose tissue? (2)
Insulation and protection of the body
Available fuel
What do fat cells look like?
Signet rings
What are Reticular CT?
Network of interwoven reticular fibers
What are examples of Reticular CT? (3)
lymphoid organs, stroma of kidney & liver, bone marrow
What do Fibrous Dense connective tissue form?
ligaments and Tendons(binds bones together)
What is the function of Fibrous Dense connective tissue?
It is the outer protective covering of organs (e.g. skin, brain, kidneys)
Describe regular dense C.T?
Collagen fibers
Rows of fibroblasts (cells that make synthesize collagen)
Where are regular dense C.T found?
In Tendons and Ligaments
Where is irregular dense C.T found?
Dermis of the skin
Describe Cartilage
Specialized form of supportive C.T. in which the extracellular matrix is firm and contains collagen
Where is cartilage found? 4
ends of long bones, larynx, trachea and bronchi
What is another name for cartilage cells?
chondrocytes
Compare cartilage to bone
Less hard and more flexible than bone
How is cartilage classified?
identified by the types of fibers in the extracellular matrix
What are the three types of cartilage?
Hyaline
Elastic
Fibrocartilage
Describe hyaline cartilage
many collagen fibers in rubbery matrix;
Glassy appearance
Where is hyaline cartilage found? 3
found in articular (joint), costal (The area in which the lung lies against the ribs) surfaces, trachea
Where is elastic cartilage found?
found in ear lobule, epiglottis.
Where is fibrocartilage found?
in intervertebral discs
Describe fibrocartilage
tough and slightly flexible
What are the two types of supportive CT?
Bone and cartilage
How is bone specialized?
It’s supportive CT where the extracellular matrix is calcified
What is the organic substance found in bone matrix?
type I collagen
What is the inorganic substance found in bone matrix?
calcium phosphate, bicarbonate, etc.
What are the two types of bone?
Compact (cortical) and Spongy (cancellous) bone
How much of the body’s bone is compact (cortical) bone
80%
What are compact (cortical) bone made of?
Made of large number tube-shaped units called osteons (Haversian systems)
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What are spongy (cancellous) bones made up of?
Made of trabeculae (small beams of compact bone), space in between contains bone marrow
What are type of tissues are responsible for movement?
Contractile tissue
What is another name for muscle cells?
myofibers
What do muscle cells contain?
contractile protein thin filaments (actin) and thick filaments (myosin)
What are the three types of muscle tissues? and their types?
Skeletal (striated)
B. Smooth (unstriated)
C. Cardiac (striated and branched)
Describe movements of skeletal muscular tissue
voluntary, quick, forceful
Describe the movement of smooth muscular tissue
involuntary, slow
Describe the movement of cardiac muscle tissue
involuntary; rhythmic
Describe skeletal muscle fibers
Long, cylindrical, multinucleated cells; the nuclei are peripheral
How thin is actin?
6nm thin
How thin is myosin?
15nm thick
Describe smooth muscle fibers?
Elongated, nonstriated, fusiform cells with single central nucleus (folded and tapers)
Where is smooth muscle fibers found? 4
Located in walls of respiratory, GIT, urinary, and blood vessels
How is the activity of smooth muscle fibers modified?
autonomic nervous system
Describe cardiac muscle fibers
Striated, branched cells with intercalated disks (junctional
complexes)
How many nuclei do cardiac muscle cell contains, and what are their description?
Contain 1–2 central large pale nuclei
Describe movement of cardiac muscles
rhythmic
What modifies the movement of cardiac muscle tissue?
autonomic N.S.
What are the two types of neural cells?
neurons and neuroglia
What are nerve cells responsible for?
reception, transmission and processing of stimuli and responses
What are the three parts of a neuron?
cell body, dendrites, axon
What are the dendrites?
cytoplasmic processes receiving stimuli
What is the axon?
the cytoplasmic process which conduct impulses from the cell body
Name the five classifications of neuroglia
1) Astrocytes
2) Oligodendrocytes
3) Microglia
4) Ependyma
5) Schwan cells
What is the function of Astrocytes?
Buffer certain chemicals in neuron
What is the functions of Oligodendrocytes
Produce myelin in central nervous system
What is the function of Schwan cells
Produce myelin in the peripheral nervous system
What is the function of ependyma
Produces cerebral spinal fluid
What is the function of microglia?
Immune cell that acts like macrophages
What is the overall function of neuroglia?
Insulate, support and protect neurons
If a stratified cuboidal tissue has more than one layer, what is it called?
Transitional cuboidal tissue
